Start by preheating your oven to 400°F (200°C) to prepare for roasting.
On a large baking sheet, arrange the halved tomatoes cut-side up. Lightly drizzle them with 1 teaspoon of olive oil and generously sprinkle with salt, freshly cracked black pepper, dried basil, and oregano for an aromatic flavor.
Take the whole head of garlic and slice off the top to expose the cloves. Drizzle a little olive oil over the exposed cloves, then wrap the entire head snugly in aluminum foil. Place this foil-wrapped garlic on the same baking sheet as the tomatoes.
Roast both the tomatoes and garlic in the preheated oven for about 30-35 minutes, or until the tomatoes are soft and edges are slightly caramelized, giving them a rich flavor.
After roasting, carefully remove the baking sheet from the oven and allow it to cool for a few minutes. Then, squeeze the roasted garlic cloves out of their skins and into either a blender or a pot.
Add the roasted tomatoes along with any juices released on the baking sheet, the finely chopped onion, vegetable broth, and balsamic vinegar to your blender (or pot) and blend until you achieve a smooth consistency. If you prefer some texture in your soup, pulse a few times to retain some chunkiness.
Transfer the blended mixture into a pot and heat it over medium heat. Allow it to simmer for about 10 minutes to meld all the flavors together. Taste the soup and adjust seasoning by adding more salt and pepper if necessary.
Serve the soup hot, beautifully garnished with fresh basil leaves for a touch of freshness. For a heartier meal, pair it with slices of crusty bread.
Notes
Drizzle a little extra virgin olive oil on top before serving for added richness.